Established in 2006, a remote Hawaiian ocean reserve called Papahānaumokuākea Marine National Monument covers 140,000 square miles and was protected in order to preserve wildlife and Hawaiian culture. Now, President Obama has more than quadrupled the reserve's boundary, making it 582,578 square miles—the largest protected area on Earth. As well as being a sanctuary for "blue whales, short-tailed albatrosses, sea turtles, and the last Hawaiian monk seals," Papahānaumokuākea has some of the healthiest coral reefs in the world. And this new decision from POTUS means it will hopefully remain that way. Read more on National Geographic.